A Brief Guide to CNC Router Glossary

CAD – Computer Aided Design.

CAM – Computer Aided Manufacturing.

CNC – Computer Numerical Control.

Climb Cut – Cutter rotates with direction of feed. Climb cutting prevents tearout, but can lead to chatter marks with a straight-fluted bit; a spiral-fluted bit will reduce chatter.

Conventional Cut – Cutter rotates against direction of feed. Results in minimal chatter but can lead to tearout in certain woods.

Feed Rate – Speed at which the cutting tool moves through the workpiece.

G-Code – A universal numerical control (NC) machine tool language that specifies axis points to which the CNC router machine will move.

Grid – The minimum movement, or feed, of the router head. Head automatically moves to next grid position when button is toggled in continuous or step mode.

Home Position (Machine Zero) – Machine-designated zero point determined by physical limit switches. (It does not identify actual work origin when processing a workpiece.)

LCD – Liquid Crystal Display (used on the controller).

PLT (HPGL) – Standard language for printing vector-based line drawings, supported by CAD files.

Spindle Speed – Rotational speed of cutting tool (RPM).

Step Down – Distance in Z-axis that the cutting tool plunges into the material.

Stepper Motor – A DC motor that moves in discrete steps by receiving signals, or “pulses” in a particular sequence, thus resulting in very precise positioning and speed control.

Step Over – Maximum distance in X or Y axis that cutting tool will engage with uncut material.

Subtractive Method – CNC Router bit removes material to create shapes. (Opposite of additive method.)

Toolpath – User-defined, coded route which the cutter follows to machine the workpiece. A “pocket” toolpath cuts the surface of the workpiece; a “profile” or “contour” toolpath cuts completely through to separate the workpiece shape.

U Disk – External data storage device that is inserted into a USB interface.

Work Origin (Work Zero) – The user-designated zero point for the workpiece, from which the CNC router head will perform all its cutting. X, Y and Z axes are set to zero.